Plant growth-promoting and antifungal activity of yeasts from dark chestnut soil

• Published in: Microbiological research 2015-06, Vol.175, p.78-83
• Main Authors: Ignatova, Lyudmila V., Brazhnikova, Yelena V., Berzhanova, Ramza Z., Mukasheva, Togzhan D.
• Format: Article
• Language: English
• Subjects: Antifungal activity; Antifungal Agents - metabolism; Aureobasidium pullulans; Biomass; DNA, Fungal - chemistry; DNA, Fungal - genetics; DNA, Ribosomal Spacer - chemistry; DNA, Ribosomal Spacer - genetics; Fabaceae; Fusarium graminearum; IAA; Molecular Sequence Data; Phytopathogens; Plant Growth Regulators - metabolism; Plant growth-promotion; Rhodotorula mucilaginosa; Sequence Analysis, DNA; Soil Microbiology; Soil yeasts; Time Factors; Yeasts - classification; Yeasts - growth & development; Yeasts - isolation & purification; Yeasts - metabolism
• ISSN: 0944-5013; 1618-0623
• DOI: 10.1016/j.micres.2015.03.008

538 yeast strains were isolated from dark chestnut soil collected from under the plants of the legume family (Fabaceae). The greatest number of microorganisms is found at soil depth 10–20cm. Among the 538 strains of yeast 77 (14.3%) strains demonstrated the ability to synthesize IAA. 15 strains were attributed to high IAA-producing yeasts (above 10μg/ml). The most active strains were YA05 with 51.7±2.1μg/ml of IAA and YR07 with 45.3±1.5μg/ml. In the study of effect of incubation time on IAA production the maximum accumulation of IAA coincided with maximum rates of biomass: at 120h for YR07 and at 144h for strain YA05. IAA production increased when medium was supplemented with the l-tryptophan. 400μg/ml of l-tryptophan showed maximum IAA production. 10 strains demonstrated the ability to inhibit the growth and development of phytopathogenic fungi. YA05 and YR07 strains formed the largest zones of inhibition compared to the other strains – from 21.6±0.3 to 30.6±0.5mm. Maximum zone of inhibition was observed for YA05 against Phytophtora infestans and YR07 strains against Fusarium graminearum. YA05 and YR07 strains were identified as Aureobasidium pullulans YA05 (GenBank accession No JF160955) and Rhodotorula mucilaginosa YR07 (GenBank accession No JF160956).